Tire and wheel assemblies

ABSTRACT

A pneumatic tire and wheel assembly including a single chamber pneumatic tire in which is provided a flowable liquid lubricant to facilitate relative movement between the internal surface of the tire which come into contact when the tire is run under load in the deflated condition, of which the following is a specification.

United States Patent [1 1 Powell et al.

[111 E Re. 28,587

[ Reissued Oct. 28, 1975 TIRE AND WHEEL ASSEMBLIES [75] Inventors:Leslie V. Powell, Lichfield; Reginald H. Edwards, Sutton Coldfield, bothof England [73] Assignee: Dunlop Holdings Limited, England [22] Filed:Apr. 5, 1974 [21] Appl. No.: 458,134

Related US. Patent Documents Reissue of:

[64] Patent No.: 3,739,829

Issued: June 19, 1973 Appl. No.: 154,326 Filed: June 18, 1971 [30]Foreign Application Priority Data June 20, 1970 United Kingdom 30033/70Apr. 3, 1971 United Kingdom 8592/71 [52] US. Cl. 152/330 [51] Int. Cl.860C 5/00 [58] Field of Search 152/330, 346, 347

[56] I References Cited UNITED STATES PATENTS 4/1943 Benson 152/33012/1971 Pace 152/327 Primary Examiner-James B. Marbert Attorney, Agent,or Firm-Stevens, Davis, Miller & Mosher [57] ABSTRACT A pneumatic tireand wheel assembly including a single chamber pneumatic tire in which isprovided a flowable liquid lubricant to facilitate relative movementbetween the internal surface of the tire which come into contact whenthe tire is run under load in the deflated condition, of which thefollowing is a specification.

37 Claims, 1 Drawing Figure Reissued Oct. 28, 1975 TIRE AND WHEELASSEMBLIES Matter enclosed in heavy brackets I: 1 appears in theoriginal patent but forms no part of this reissue specification; matterprinted in italics indicates the additions made by reissue.

This invention relates to tire/wheel assemblies.

Upon partial or complete deflation of a pneumatic tire mounted on awheel during the running of a vehicle oppositesurfaces in the interiorof the tire and wheel assembly come into contact with one another undermore or less load according to whether or not deflation iscomplete,.considerable heat is generated within the rubber and textilecomponents of the tire and very rapid structural failure ensues.

One approach to this problem in the past has been to provide a second,independent, air chamber inside the tire so that if the tire ispunctured the second chamber remains inflated and prevent the tire fromcollapsing and running on the rim. The disadvantages of this type ofconstruction are that it is expensive and adds weight to the tire andhence adds to the unsprung weight ofa vehicle on which it is used. Agrave problem is also that the inner chamber chafes on the interior ofthe outer chamber of the tire even, in the bead region at least, duringnormal running of the tire. To combat this problem it has been proposedto lubricate the surface of the inner chamber and/or inner surface ofthe outer chamber with a suitable coating. Low profile tires e.g. ofaspect ratio 30 percent to 75 percent present a further problem in thatthe low sectional height allows little height for an inner chamber toprevent the tire bottoming on the rim.

The regions of the interior surfaces of a single chamber pneumatic tirewhich normally come into contact when running in the deflated conditionare the interior surfaces of the tire close to but radially outwardly ofthe rim flange and the interior surfaces of the tire close to butradially-inwardly of the tread edgeQIt has been discovered that themajor source of the heat generated which leads to the failure of thetire, is the relative movement of the interior surfaces of the tirewhich are in contact and under load.

According to the present invention a pneumatic tire and wheel assemblycomprises a single chamber pneumatic tire wherein a flowable liquidlubricant is provided for the lubrication of the interior surfaces ofthe tire whereby in use of said assembly with the tire in a deflated orsubstantially under-inflated condition the relative movement between theinterior surfaces of the tire in contact with one another isfacilitated.

The liquid lubricant preferably is miscible with water so that leakagefrom a tire and wheel assembly onto a road surface can be washed awayalthough a water insoluble lubricant can be used if desired. It is alsodesirable that the lubricant should not freeze at temperatures above Cso as to withstand cold weather. The liquid lubricant may have a boilingpoint of at least 90C and preferably, in order to withstand hightemperatures without severe loss through volatilization a liquidcomponent of the lubricant has a vapor pressure of less than 50 mm ofmercury at 140 C.

The liquid lubricant advantageously has a viscosity which is as high asis practicable to minimize lubricant loss through a puncture and assistin sealing a puncture bearing in mind the need for the lubricant to flowinto the portions of the tire interior requiring lubrication. Thepreferred viscosity range for the liquid lubricant is 10,000 to 200,000centistokes at 38C. Preferably also the lubricant although having a highviscosity has a low resistance to shear i.e. is a thixotropic material.

The liquid lubricant preferably has no deleterious effect on the rubberor other component of the tire carcass. If desired liquid lubricantswhich normally swell or otherwise affect rubber could be used by the useof a special impervious protective inner liner in the tire.

The liquid lubricant may, with advantage, contain a volatile liquid,which may or may not itself act as a lubricant for the rubber but whichhas a boiling point sufficiently low to appreciably volatilize at thetemperature generated by running of the tire in a deflated or partlydeflated condition. In this way the volatile liquid functions topartially re-inflate the tire and so reduce the high stresses generatedin the sidewall due to the deflated or substantially deflated condition.Heat build-up in the tire is also lowered due to the reduced contactpressure and hence reduced frictional forces between the interior tiresurfaces. The volatilizing of the volatile liquid also assists thedissipation of heat over the entire tire and rim surface. The volatileliquid has a vapor pressure at C above 200 mm. of mercury and may have aboiling point below for example C but preferably not below, for example70 C in order that the liquid may be readily handled and not volatilizedappreciably during normal running of the tire.

The volatile liquid, may itself be used to form the basis of thelubricant, e.g. an aqueous gel, although it is then particularlypreferable to include in the lubricant some puncture sealing material inorder to at least partly seal a puncture occurring in the tire tominimize the rate at which lubricant is lost from the tire.

Preferably the liquid lubricant containing a volatile liquid comprises ahigh boiling point lubricant, e.g. glycerol, and a volatile liquid whichneed not necessarily have good lubricating properties, e.g. water, sothat if all the volatile liquid is lost as vapor from the tire the highboiling point lubricant remains. The liquids may or may not be misciblewith each other.

In the case of liquid lubricants containing water as the volatile liquidviscosities in the range 10,000 to 200,000 centistokes, and good.lubricant properties can be achieved by the use of gelling agents suchas those available under the trade names Natrosol, Polysteric BN4 andCarbopol. Viscous liquid lubricants such as gelled water-basedlubricants have the added advantage that they assist in sealing apuncture at least against the low, e.g. 4 psi. pressures produced byvapor pressure inflation.

When the lubricant contains a volatile component it is most desirablethat the lubricant should be capable of sealing the puncture. Thus theliquid lubricant may have incorporated therein a separatepuncture-sealing or reducing material, for example, chopped cotton,wool, asbestos or synthetic fibers, e.g. of 0.0001 inch diameter andabout 0.1 inch'long which acts to form a matted barrier over a punctureand is carried into position by escaping inflationary air and/orlubricant.

A liquid lubricant based on an aqueous gel may contain, for example, afreeze point lowering agent such as ethylene glycol or glycerol andagents to increase the lubricating power such as molybdenum disulphide,

isocrsable graphite powder and/or wetting agent or etergent such asTeepol.

It may be advantageous for the liquid lubricant to ave a formulationwhich enables the lubricant to be ample in the tire mentioned aboveusing water as a volatile component at least 5 I: millimeters Imilliliters of water should be used, although a considerably largervolume would generally be used to ensure a rapid increase in pressure inthe,tire and allow for possible losses.

The liquid lubricant may be taken from a wide range of classes ofcompounds which are lubricants for rubber to rubber interfaces, forexample:

e.g. arachis. castor. linseed. olive,

palm, rape. turkey red.

e.g. n'octanol.

e.g. diethyl sulphate, methyl caprylate.

Non-ionic surface active agents Cationic surface active agents Anionicsurface active agents Polyglycols (sometimes called glycols.

polyethers, polyalkylene glycols or polyoxyalkylene glycols), e.g. "Ucon5O HB-ZOOO and SO-HB-l'lO.

Dibasic acid esters e.g. dimethyl oxalate Chlorofluorocarbon polymersSilicones Silicate esters Fluoroe ste rs Neopentyl polyol estersPolyphenyl ethers Tetra alkyl silanes Ferrocene derivativesTetra-substituted urea derivatives Heterocyclic derivatives Aromaticamines Hexafluorobenzene Soaps (e.g. sodium stearate) Alkalis (e.g.sodium hydroxide in weak LC of a detergent in a lubricant containingwaterv A deaming agent may also be used in the lubricant com- )sition tocontrol the extent of foaming, or if desired, event foaming.

A dispersant may be used when fibers are incorpoted in the composition.

The total amount of liquid lubricant in the tire is a inor proportion ofthe total volume of the tire, being preciably less, for example, that]than the large )lume of water used as ballast in agricultural and simirtype tires which [as is a major proportion e.g. t'the interior volume ofthe tires. Such large volumes the present invention would be quiteimpractical n'ce they impair the running properties of the tire, cre- .ehigh rolling resistance and prevent the tire from sing used at anythingother than low speeds. in the resent invention, the amount of liquidlubricant deands upon the lubricant used and the internal surface ea ofthe inflation chamber of the tire but for examle in a l85/60-l 3 radialply car tire of internal volume oproximately 28 liters the total amountof lubrication ill generally be at least 75 millimeters] milliliters utpreferably less than e.g. l liter since above this volme the liquid isbecoming undesirably heavy and ulky. This corresponds to between 105 and1,300 :millimeters] milliliters oflubricant per square meter finternalsurface area of the tire.

In the case of a lubricant containing a volatile comonent sufficientvolatile component should preferably e present to generate in a volumeat least 4 times that fthe inflation chamber of the tire a pressure ofat least psi. at a temperature of for example, 68C. For Ex solutions).

Some examples of specific compounds which may be used are sodiumcarboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropylcellulose, silicone oil, glycerol, propylene glycol, Teepol (a detergentcommer cially available from Shell), Hederol" (a detergent commerciallyavailable from Proctor and Gamble), or mixtures thereof.

Examples of liquid lubricants containing a volatile component aresolutions of detergents e.g. Teepol" in water, aqueous gels containinge.g. hydroxyethyl cellulose with or without a high boiling point such asglycerol, and mixtures of polyglycols or glycerol with water.

In addition to the puncture sealing and other additives previouslymentioned the liquid lubricant may contain other substances such asantioxidants, to prevent oxidative attack on the lubricant, bactericide,wetting agent and viscosity index improver [r0] to broaden the range oftemperatures at which the lubricant has a satisfactory viscosity.

In order to minimize the weight of lubricant required and anydetrimental effects on the balance of the wheel/tire assembly the liquidlubricant preferably has a relatively low specific gravity e.g. aspecific gravity less than 1.4.

In order to maintain a degree of lateral stability even when deflated,the tire preferably has a fairly low aspect ratio e.g. 30 percent to 75percent and preferably 55 percent to percent and the width of the tiretread is preferably greater than the width of the wheel rim measuredbetween the flanges. lf desired a tire having a cantilever sidewallconstruction may be used e.g. that described in I. U.K. Patentapplication No.

26702/70. U.S. Patent Application No. 145,610 filed May 21, 1971. Thewheel rim upon which the tire is mounted is preferably a flat orsubstantially flat base rim without a well into which the tire beads canfall if they are displaced from their seats.

Two suitable types of rim which can be used are split rims, where therim is divisible to permit mounting of a tire thereon and axiallycompressed rims which are rims produced initially with a well, the wellbeing closed by axial compression after the tire has been mountedthereon, the latter type is shown in the accompanying drawing. When therim has no well, if the beads become displaced from their seats in theground contact area of the tire it is possible for them to be returnedto their correct positions by the forces generated during rotation ofthe wheel in normal straight ahead driving although means for positivelyretaining at least the laterally outer bead in its seat may be providedif desired. lfa well-base rim is used, means are provided for retainingthe beads in their seats, e.g. a bead spacer ring or removable studs orprojections on the wheel rim.

Two particular examples of carrying out the invention will now bedescribed with reference to the accompanying drawing of a cross sectionof a tire I mounted on a wheel rim 2 and containing liquid lubricant 3.

Two gelled solutions ofa water-based liquid lubricant were made up asindicated in Table 1 below:

TABLE I Solution Solution 1 (thin) 2 (thick) Teepol S (containing sodiumsalts of alkylaryl sulphonates and secondary alkyl sulphonates) 5 ml. 5ml. Water 95 ml. 95 ml. 2% Belloid T.D. disperant (sodiumdinaphthylmethane disulphonate 80% active made by Geigy) 5 ml. 5 ml.Asbestos (Canadian Group 7 l6 (Floats) very short low gl'lt 7 T.F.l.supplied by Johns-Manville) 2 g. 2 g. Defoamer C.V.P. (made by CrayValley Products) 1 ml. 1 ml. Natrosol 260 H.H.R. thickener (watersolublehydroxyethyl cellulose supplied by Hercules Powder Co. Ltd.) 1 g. l.5 g.Viscosity 10.000 100,000 centi centistokes stokes 500 [millimeters]milliliters of this lubricant was introduced into the inflation chamberof a pneumatic tire (size 185/60 X 13) mounted on a 3.5013 wheel rim(see drawing).

When a tire lubricated by means of the liquid as described above isdeflated or substantially deflated, opposite parts of the interiorsurfaces of the tire or tire and wheel assembly come into contact andthat part of the load of the vehicle which is supported by the tire andwheel assembly is carried by those surfaces, substantial relativemovement taking place between them.

However, since the contacting surfaces are lubricated, the coefficientof friction is very low and little heat is generated, insufficient tocause structural damage or changes to the tire which might cause a rapidnoticeable deterioration in the control of the vehicle. The vehicle onwhich the wheel and tire were mounted was thus enabled safely to travelsubstantial distances e.g. or more miles at a reasonable speed, eg 40m.p.h.,

TABLE II Water 7U ml. Glycerol 30 ml. Natrosol I250 HHR. 2 gm. Hede rol(detergent made by Proctor & Gamble) l ml.

A l/60-l3 radial ply tire containing 300 millimeters of'this lubricantwas run under 400 lbs load against a rotating drum at 50 m.p.h. and thedrag generated by the tire i.e. its resistance to rotation was measured.The initial drag was 35.6 lbs but this value reduced steadily over the10 minute run to a final figure of 20.1 lbs. After the 10 minutes thetire was found to be inflated to 3.5 psi.

Various further tests were performed using similar tires on the sametest rig. In these tests however, the tires were run at 30 m.p.h. andthe temperature generated in the shoulder of the tire were measuredafter 10 minutes and 20 minutes. To obtain a strict comparison betweenlubricating properties in these further tests care was taken to ensurethat the tire did not become inflated.

Firstly, a series of tests was performed to investigate the effect ofvarying the amount of lubricant. Table III below gives the resultsobtained using as lubricant a polyalkylene glycol (availablecommercially as UCON oil) having a viscosity of 433 centistokes.

Table [V below gives the results obtained using as lubricant a 50/50mixture of the polyalkylene glycol used in the tests in Table I andwater.

Table V below gives the results obtained using as lubricant theglycerol/aqueous gel lubricant whose [formation formulation is givenabove.

TABLE V- Volume of Type/Viscosity Temperatures (C) after lubricantCentistokes at 38C Water/Glycerol/Nitrosol/Hederol l00,000 10 mins.mins. Ambient 300 c.c. (70/30) 90 110 18 200 cc. 108 122 20 c.c. H5 12522 50 cc 125 I 22 tion may also be used with the inventions described in[U.K.] U.S. Patent application Nos. [30029/70, 30030/70, 30031/70,30032/70 and 07024/71] 150,628,I50,561,150,564,150,560 allfiled on June7, 1971 and 232,850 filed on March 8, I972.

The invention applies to tire and wheel assemblies in which the tire canbe removed from the rim or, alternatively, when the tire is notremovable therefrom i.e. the two form a permanent assembly, for example,when the rim is swaged over the tire beads after assembly of tire andrim.

temperature which after 10 minutes is as low as or lower than the otherlubricants but after a certain level of temperature in. the .tireisreached the temperature begins to rise very rapidly so that after 20minutes the temperatures of the water-containing tire has risen to 150 Cwhich is approaching tire failure.

If lubricant should leak onto the road surface, when it is water-basedor miscible with water it can be washed away by rainfall, so as toprevent the build-up of a hazard. to other road vehicles by thereduction of the coefficient of the road surface below a safe level.

When a liquid lubricant containing a volatile component is used it maybe desirable to include in the wheel rim or tire a safety pressurerelease valve or other de vice e.g. a safety plug to prevent the tirefrom becoming over-inflated. However, as the increasing internalpressure increases the boiling point of the liquid lubricant, it isadvantageous to design the lubricant so that its boiling point, at themaximum permissible tire inflation pressure has increased to above themaximum permissible generated temperature, so that boiling of the lubricant stops before the tire can become severely overinflated.

In the present invention the liquid lubricant may be inserted directlyinto the inflation chamber of the tire before the tire and wheelassembly is sold, preferably, however, the lubricant is provided in anenclosing means which releases the lubricant into the tire upondeflation as described in I: U.K.] U.S. Patent application No.[30027/70] 150,627filed June 7, 1971 (interior lubricant container).Alternatively the lubricant may be injected into the tire afterdeflation as described in [U.K.] U.S. Patent application No. [30028/70]150,562 filed June 7, 1971. The inven- TABLE VI Type Viscosity Centi-Temperature (C) after Stokes at 38C 10 mins. 20 mins. Ambient Glycerol224 118 123 25 Propylene Glycol 46 l 15 26 Silicone oil 470 105 12523/24 Silicone oil 20 H7 l3 0 22 Water 0.7 100 I50 20 UCON oil(polyalkylene glycol) 433 N7 l35 l9 It will be seen that water initiallymaintains a low We claim:

l. A pneumatic tire and wheel assembly having a single inflation chambercapable of being run in a deflated condition comprising:

1. a wheel having a wheel rim with a pair of opposed annular flanges;

2. a pneumatic tire having a tread portion whose width is greater thanthe width of the wheel rim measured between the flanges and in which thewheel rim upon which the tire is mounted is substantiallyflat basedwithout a well into which the tire beads can fall if they are displacedfrom their seats, the rim being divisible to permit mounting ofthe tirethereon;

3. a flowable liquid lubricant which, when the assembly is used with thetire in a deflated condition, will facilitate relative movement ofcontacting interior surfaces of the tire.

5. The pneumatic tire and wheel assembly of claim 1, i

in which the liquid lubricant includes some puncture sealingmaterial inorder to at least partially seal a puncture occuring in the tire.

6. The pneumatic tire and wheel assembly of claim 1, in which the liquidlubricant has a specific gravity less than 1.4

7; The pneumatic tire and wheel assembly of claim 1, in which the tirehas an aspect ratio between 30 percent and 75'percent.

8. The pneumatic tire and wheel assembly of claim 7, in which the aspectratio of the tire is in the range 55 perce'ritto 70percent.

[9. The pneumatic tire and wheel assembly of claim 1, in which the wheelrim upon which the tire is mounted is substantially flat based without awell into which the tire beadscan fall if they are displaced from theirseats, the rim being divisible to permit mounting of the tire thereon][10. The pneumatic tire and wheel assembly of claim l, in which thewheel rim upon which the tire is mounted is produced initially with awell to permit mounting'of the tire on the rim, the well being closed byaxial compression after the tire has been mounted thereon] 11. Thepneumatic tire and wheel assembly of claim 7 1, in which the liquidlubricant contains a volatile liquid which has a boiling pointsufficiently low to appreciably volatilize at the temperature generatedby running of the tire in a deflated or partly deflated condition.

The pneumatic tire and wheel assembly of claim 1, in which the totalamount of lubricant in the tire is in the range of 105 to 1,300 mls oflubricant per square meter of internal surface area of thetire.

13. The pneumatic tire and wheel assembly of claim I, in which theliquid lubricant has a formulation which enables the lubricant to befrothed or foamed by the violent agitation caused by rotation of thetire and wheel assembly.

14. The pneumatic tire and wheel assembly of claim l] l3 iincluding a[deforming defoa ming agent to claim l, in which the rim has an area ofexcess material bent. so as to leave the rim substantially without awell between the flanges.

16. A pneumatic tire and wheel assembly having a single inflationchamber capable of being run in a deflated condition comprising:

a.,A wheel having a wheel rim with a pair of opposed annular flanges;

b, A pneumatic tire having a tread portion whose width is greater thanthe width of the wheel rim measured between the flanges, and in whichthe wheel rim upon which the tire is mounted is produced initially vwith a well to permit mounting ofthe tire on the rim,

-. the well being closed by axial compression after the tire has beenmounted thereon;

c-. A flowable liquid lubricant which, when theassembly is-used with thetire in a deflated condition, will facilitate relative movement ofcontacting interior surfaces of the tire.

I 7. A pneumatic tire and wheel assembly having a single inflationchamber capable of being run in a deflated condition comprising:

a. A wheel having a wheel rim with a pair of opposed annular flanges,

b. A pneumatic tire having a tread portion whose width is greater thanthe width of the wheel rim measured between the flanges;

c. A flowable liquid lubricant which, when the assembly is used with thetire in a deflated condition, will facilitate relative movement ofcontacting interior surfaces of the tire, and in which the liquidlubricant contains a volatile liquid which has a boiling pointsufficiently low to appreciably volatilize at the temperature generatedby running of the tire in a deflated or partly deflated condition.

18; The pneumatic tire and wheel assembly of claim 17, in which theliquid lubricant is miscible with water.

19. The pneumatic tire and wheel assembly of claim 17. in which theliquid lubricant does not freeze at temperatures above 20 C.

20. The pneumatic tire and wheel assembly of claim 1 in which at leastone liquid component of the lubricant has a vapor pressure ofless than50 mm ofmercury at 140 c.

21. The pneumatic tire and wheel assembly of claim 17, in which theliquid lubricant includes some puncture sealing material in order to atleast partially seal a puncture occurring in the tire.

22. The pneumatic tire and wheel assembly of claim 17. in which theliquid lubricant has a specific gravity less than 1.4. I

23.' The pneumatic tire and wheel assembly of claim I 17, in which thetire has an aspect ratio between 30% and 75%.

24. The pneumatic tire and wheel assembly of claim 23, in which theaspect ratioof the tire is in the range of 55% to v t 25. A pneumatictire and wheel assembly having a single inflation chamber capable ofbeing run in a deflated condition comprising.

a. A wheel having a wheel rim with a pair of opposed annularflanges, andin which the rim has an area of excess material bent so as to leave therim substan' tially without a well between the flanges;

b. A pneumatic tire having a tread portion whose width is greater thanthe width of wheel rim measured between the flanges;-

c. A flowable liquid lubricant which, when the assembly is 'used withthe tire in a deflated condition, will facilitate relative movement ofcontacting interior surfaces of the tire.

26. A pneumatic tire and wheel assembly capable of being run in adeflated condition and having a single inflation chamber comprising:

' a. A wheel having a wheel rim with a pair ofopposed annularflang esand a substantially flat base rim between said flanges so that the wheelrim is without a well into which the tire beads can fall, and a beadretaining means for restraining at least the laterally outer beadfrommoving from its seat;

b. A pneumatic tire havingan aspect ratio of between 30% and a treadportion whose widthis greater than the width of the wheel rim measuredbetween the flanges and flowable lubricating material disposed on aninterior surface of the tire which, when the assembly is used with thetire in a deflated condition, will facilitate relative movement ofcontacting interior surfaces of the tire.

27. A pneumatic tire and wheel assembly capable of being run in adeflated condition and having a single inflation chamber comprising: 7

a. A wheel having a wheel rim with a pair ofopposed annular flanges, apair of bead seats adjacent said flanges and a well to permit a tire tobe mounted on the rim, means being provided for physically restrainingthe beads in their seats to prevent the tire beads from falling into thewell, said means being movable to permit the tire to be dismountedfromthe rim;

. A pneumatic tire having a tread portion whose width is greater thanthe width of the wheel rim measured between the flanges and aflowablelubricating material disposed on an interior surface ofthe tire, the entire interior of said tire being free of intermediate supportingstructure and the entire interior surface ofsaid tire being freeofinterrnediate protruding supporting structure so that when the tire isin a deflated condition opposed portions of the interior surface of thetire are movable relative to each other without generating an undueamount ofheat by means ofthe lubricating material, which, when theassembly is used with the tire in a deflated condition, will facilitaterelative movement of contacting interior surfaces of the tire.

28. A pneumatic tire and wheel assembly capable of being run in adeflated condition and having a single inflation chamber comprising:

a. A wheel having a wheel rim with a pair of opposed annularflanges anda substantially flat base rim between said flanges so that the wheel rimis without a well into which the tire beads can fall;

b. A pneumatic tire having a tread portion whose width is greater thanthe width of the wheel rim measured between the flanges, an aspect ratiobetween 30% and 75% and a flowable liquid lubricating material disposedinside the tire which, when the assembly is used with the tire in adeflated condition, will facilitate relative movement of contactinginterior surfaces of the tire.

29. The pneumatic tire and wheel assembly of claim 28, in which thelubricating material is miscible with water.

30. The pneumatic tire and wheel assembly of claim 28, in which thelubricating material does not freeze at temperatures above 20 C.

31. The pneumatic tire and wheel assembly of claim 28, in which at leastone liquid component of the lubricating material has a vapor pressure ofless than 50 mm ofmercury at 140C.

32. The pneumatic tire and wheel assembly of claim 28, in which thelubricating material includes some puncture sealing material in order toat least partially seal a puncture occurring in the tire.

33. The pneumatic tire and wheel assembly of claim 28, in which thelubricating material has a specific gravity less than 1.4.

34. The pneumatic tire and wheel assembly of claim 28, in which theaspect ratio ofthe tire is in the range of 55% to 70%.

35. The pneumatic tire and wheel assembly of claim 28, in which thetotal amount of lubricating material in the tire is in the range ofl to1,300 mls. of lubricant per square meter of internal surface area of thetire.

36. The pneumatic tire and wheel assembly of claim 28, in which thelubricating material hasa formulation which enables the lubricant to befrothed or foamed by the violent agitation caused by rotation of thetire and wheel assembly.

37. The pneumatic tire and wheel assembly of claim 28, including adefoaming agent to control the extent of foaming.

38. A pneumatic tire and wheel assembly having a sinvgle inflationchamber capable of being run in a deflated condition comprising:

a. A wheel having a wheel rim with a pair of opposed annular flanges, apneumatic tire mounted on the rim and having a pair of beads between theflanges and means on the rim to prevent the beads from becomingdislodged from the rim when run in a deflated condition;

. aflowable liquid lubricant which, when the assembly is used in adeflated condition, will facilitate relative movement ofcontactinginterior surfaces of the tire, said liquid lubricant containing avolatile liquid which has a boiling point sufficiently low toappreciably volatilize at the temperature generated by running of thetire in a deflated or partly deflated condition and a puncture sealingmaterial to at least partially seal a puncture occurring in the tire.

39. A pneumatic tire and wheel assembly capable of being run in adeflated condition and having asingle inflation chamber comprising:

a. A wheel having a wheel rim with a pair ofopposed annular flange and asubstantially flat base rim between said flanges so that the wheel rimis without a well into which the tire beads can fall, and a beadretaining means for restraining at least the laterally outer beadfrommoving from its seat;

b. A pneumatic tire having an aspect ratio of between 30% and a treadportion whose width is greater than the width of the wheel rim measuredbetween the flanges and flowable lubricating material disposed on aninterior surface ofthe tire, the entire interior ofsaid tire being freeof intermediate supporting structure and the entire interior surface ofsaid tire being free ofintermediate protruding supporting structure sothat when the tire is in a deflated condition opposed portions of theinterior surface of the tire are movable relative to each other withoutgenerating an undue amount ofheat by means ofthe lubricating material,which, when the assembly is used with the tire in a deflated condition,will facilitate relative movement of contacting interior surfaces of thetire.

40. A pneumatic tire and wheel assembly capable of being run in adeflated condition and having a single inflation chamber comprising:

a. A wheel having a wheel rim with a pair of opposed annularflanges anda substantially flat base rim between said flanges so that the wheel rimis without a well into which the tire beads can fall;

b. A pneumatic tire having a tread portion whose width is greater thanthe width of the wheel rim measured between the flanges, an aspect ratiobetween 30% and 75% and a flowable liquid lubricating material disposedinside the tire, the entire interior ofsaid tire being free ofintermediate supporting structure and the entire interior surface ofsaidtire being free ofintermediate protruding supporting structure so thatwhen the tire is in a deflated condition opposed par tions of theinterior surface of the tire are movable relative to each other withoutgenerating an undue amount ofheat by means ofthe lubricating material,

which, when the assembly is used with the tire in a deflated condition,will facilitate relative movement of contacting interior surface of thetire.

1. A pneumatic tire and wheel assembly having a single inflation chambercapable of being run in a deflated condition comprising:
 1. a wheelhaving a wheel rim with a pair of opposed annular flanges;
 2. apneumatic tire having a tread portion whose width is greater than thewidth of the wheel rim measured between the flanges(;) and in which thewheel rim upon which the tire is mounted is substantially flat basedwithout a well into which the tire beads can fall if they are displacedfrom their seats, the rim being divisible to permit mounting of the tirethereon;
 3. a flowable liquid lubricant which, when the assembly is usedwith the tire in a deflated condition, will facilitate relatIve movementof contacting interior surfaces of the tire.
 2. a pneumatic tire havinga tread portion whose width is greater than the width of the wheel rimmeasured between the flanges(;) and in which the wheel rim upon whichthe tire is mounted is substantially flat based without a well intowhich the tire beads can fall if they are displaced from their seats,the rim being divisible to permit mounting of the tire thereon;
 2. Thepneumatic tire and wheel assembly of claim 1, in which the liquidlubricant is miscible with water.
 3. a flowable liquid lubricant which,when the assembly is used with the tire in a deflated condition, willfacilitate relatIve movement of contacting interior surfaces of thetire.
 3. The pneumatic tire and wheel assembly of claim 1, in which theliquid lubricant does not freeze at temperatures above -20* C.
 4. Thepneumatic tire and wheel assembly of claim 1, in which at least oneliquid component of the lubricant has a vapor pressure of less than 50mm of mercury at 140* C.
 5. The pneumatic tire and wheel assembly ofclaim 1, in which the liquid lubricant includes some puncture sealingmaterial in order to at least partially seal a puncture occuring in thetire.
 6. The pneumatic tire and wheel assembly of claim 1, in which theliquid lubricant has a specific gravity less than 1.4
 7. The pneumatictire and wheel assembly of claim 1, in which the tire has an aspectratio between 30 percent and 75 percent.
 8. The pneumatic tire and wheelassembly of claim 7, in which the aspect ratio of the tire is in therange 55 percent to 70 percent.
 11. The pneumatic tire and wheelassembly of claim 1, in which the liquid lubricant contains a volatileliquid which has a boiling point sufficiently low to appreciablyvolatilize at the temperature generated by running of the tire in adeflated or partly deflated condition.
 12. The pneumatic tire and wheelassembly of claim 1, in which the total amount of lubricant in the tireis in the range of 105 to 1,300 mls of lubricant per square meter ofinternal surface area of the tire.
 13. The pneumatic tire and wheelassembly of claim 1, in which the liquid lubricant has a formulationwhich enables the lubricant to be frothed or foamed by the violentagitation caused by rotation of the tire and wheel assembly.
 14. Thepneumatic tire and wheel assembly of claim (1) 13 including a(deforming) defoaming agent to control the extent of foaming.
 16. Apneumatic tire and wheel assembly having a single inflation chambercapable of being run in a deflated condition comprising: a. A wheelhaving a wheel rim with a pair of opposed annular flanges; b. Apneumatic tire having a tread portion whose width is greater than thewidth of the wheel rim measured between the flanges, and in which thewheel rim upon which the tire is mounted is produced initially with awell to permit mounting of the tire on the rim, the well being closed byaxial compression after the tire has been mounted thereon; c. A flowableliquid lubricant which, when the assembly is used with the tire in adeflated condition, will facilitate relative movement of contactinginterior surfaces of the tire.
 17. A pneumatic tire and wheel assemblyhaving a single inflation chamber capable of being run in a deflatedcondition comprising: a. A wheel having a wheel rim with a pair ofopposed annular flanges; b. A pneumatic tire having a tread portionwhose width is greater than the width of the wheel rim measured betweenthe flanges; c. A flowable liquid lubricant which, when the Assembly isused with the tire in a deflated condition, will facilitate relativemovement of contacting interior surfaces of the tire, and in which theliquid lubricant contains a volatile liquid which has a boiling pointsufficiently low to appreciably volatilize at the temperature generatedby running of the tire in a deflated or partly deflated condition. 18.The pneumatic tire and wheel assembly of claim 17, in which the liquidlubricant is miscible with water.
 19. The pneumatic tire and wheelassembly of claim 17, in which the liquid lubricant does not freeze attemperatures above -20* C.
 20. The pneumatic tire and wheel assembly ofclaim 17, in which at least one liquid component of the lubricant has avapor pressure of less than 50 mm of mercury at 140* C.
 21. Thepneumatic tire and wheel assembly of claim 17, in which the liquidlubricant includes some puncture sealing material in order to at leastpartially seal a puncture occurring in the tire.
 22. The pneumatic tireand wheel assembly of claim 17, in which the liquid lubricant has aspecific gravity less than 1.4.
 23. The pneumatic tire and wheelassembly of claim 17, in which the tire has an aspect ratio between 30%and 75%.
 24. The pneumatic tire and wheel assembly of claim 23, in whichthe aspect ratio of the tire is in the range of 55% to 70%.
 25. Apneumatic tire and wheel assembly having a single inflation chambercapable of being run in a deflated condition comprising: a. A wheelhaving a wheel rim with a pair of opposed annular flanges, and in whichthe rim has an area of excess material bent so as to leave the rimsubstantially without a well between the flanges; b. A pneumatic tirehaving a tread portion whose width is greater than the width of wheelrim measured between the flanges; c. A flowable liquid lubricant which,when the assembly is used with the tire in a deflated condition, willfacilitate relative movement of contacting interior surfaces of thetire.
 26. A pneumatic tire and wheel assembly capable of being run in adeflated condition and having a single inflation chamber comprising: a.A wheel having a wheel rim with a pair of opposed annular flanges and asubstantially flat base rim between said flanges so that the wheel rimis without a well into which the tire beads can fall, and a beadretaining means for restraining at least the laterally outer bead frommoving from its seat; b. A pneumatic tire having an aspect ratio ofbetween 30% and 75%, a tread portion whose width is greater than thewidth of the wheel rim measured between the flanges and flowablelubricating material disposed on an interior surface of the tire which,when the assembly is used with the tire in a deflated condition, willfacilitate relative movement of contacting interior surfaces of thetire.
 27. A pneumatic tire and wheel assembly capable of being run in adeflated condition and having a single inflation chamber comprising: a.A wheel having a wheel rim with a pair of opposed annular flanges, apair of bead seats adjacent said flanges and a well to permit a tire tobe mounted on the rim, means being provided for physically restrainingthe beads in their seats to prevent the tire beads from falling into thewell, said means being movable to permit the tire to be dismounted fromthe rim; b. A pneumatic tire having a tread portion whose width isgreater than the width of the wheel rim measured between the flanges anda flowable lubricating material disposed on an interior surface of thetire, the entire interior of said tire being free of intermediatesupporting structure and the entire interior surface of said tire beingfree of intermediate protruding supporting structure so that when thetire is in a deflated condition opposed portions of the interior surfaceof the tire are movable relative to each other without generating anundue amount of heat by means of the lubricating material, which, whenthe assembly is used with the tire in a deflated condition, willfacilitate relative movement of contacting interior surfaces of thetire.
 28. A pneumatic tire and wheel assembly capable of being run in adeflated condition and having a single inflation chamber comprising: a.A wheel having a wheel rim with a pair of opposed annular flanges and asubstantially flat base rim between said flanges so that the wheel rimis without a well into which the tire beads can fall; b. A pneumatictire having a tread portion whose width is greater than the width of thewheel rim measured between the flanges, an aspect ratio between 30% and75% and a flowable liquid lubricating material disposed inside the tirewhich, when the assembly is used with the tire in a deflated condition,will facilitate relative movement of contacting interior surfaces of thetire.
 29. The pneumatic tire and wheel assembly of claim 28, in whichthe lubricating material is miscible with water.
 30. The pneumatic tireand wheel assembly of claim 28, in which the lubricating material doesnot freeze at temperatures above -20* C.
 31. The pneumatic tire andwheel assembly of claim 28, in which at least one liquid component ofthe lubricating material has a vapor pressure of less than 50 mm ofmercury at 140*C.
 32. The pneumatic tire and wheel assembly of claim 28,in which the lubricating material includes some puncture sealingmaterial in order to at least partially seal a puncture occurring in thetire.
 33. The pneumatic tire and wheel assembly of claim 28, in whichthe lubricating material has a specific gravity less than 1.4.
 34. Thepneumatic tire and wheel assembly of claim 28, in which the aspect ratioof the tire is in the range of 55% to 70%.
 35. The pneumatic tire andwheel assembly of claim 28, in which the total amount of lubricatingmaterial in the tire is in the range of 105 to 1,300 mls. of lubricantper square meter of internal surface area of the tire.
 36. The pneumatictire and wheel assembly of claim 28, in which the lubricating materialhas a formulation which enables the lubricant to be frothed or foamed bythe violent agitation caused by rotation of the tire and wheel assembly.37. The pneumatic tire and wheel assembly of claim 28, including adefoaming agent to control the extent of foaming.
 38. A pneumatic tireand wheel assembly having a single inflation chamber capable of beingrun in a deflated condition comprising: a. A wheel having a wheel rimwith a pair of opposed annular flanges, a pneumatic tire mounted on therim and having a pair of beads between the flanges and means on the rimto prevent the beads from becoming dislodged from the rim when run in adeflated condition; b. a flowable liquid lubricant which, when theassembly is used in a deflated condition, will facilitate relativemovement of contacting interior surfaces of the tire, said liquidlubricant containing a volatile liquid which has a boiling pointsufficiently low to appreciably volatilize at the temperature generatedby running of the tire in a deflated or partly deflated condition and apuncture sealing material to at least partially seal a punctureoccurring in the tire.
 39. A pneumatic tire and wheel assembly capableof being run in a deflated condition and having a single inflationchamber comprising: a. A wheel having a wheel rim with a pair of opposedannular flange and a substantially flat base rim between said flanges sothat the wheel rim is without a well into which the tire beads can fall,and a bead retaining means for restraining at least the laterally outerbead from moving from its seat; b. A pneumatic tire having an aspectratio of between 30% and 75%, a tread portion whose width is greaterthan the width of the wheel rim measured between the flanges andflowable lubricating material disposed on an interior surface of thetire, the entire interior of said tire being free of intermediatesupporting structure and the entire interior surface of said tire beingfree of intermediate protruding supporting structure so that when thetire is in a deflated condition opposed portions of the interior surfaceof the tire are movable relative to each other without generating anundue amount of heat by means of the lubricating material, which, whenthe assembly is used with the tire in a deflated condition, willfacilitate relative movement of contacting interior surfaces of thetire.
 40. A pneumatic tire and wheel assembly capable of being run in adeflated condition and having a single inflation chamber comprising: a.A wheel having a wheel rim with a pair of opposed annular flanges and asubstantially flat base rim between said flanges so that the wheel rimis without a well into which the tire beads can fall; b. A pneumatictire having a tread portion whose width is greater than the width of thewheel rim measured between the flanges, an aspect ratio between 30% and75% and a flowable liquid lubricating material disposed inside the tire,the entire interior of said tire being free of intermediate supportingstructure and the entire interior surface of said tire being free ofintermediate protruding supporting structure so that when the tire is ina deflated condition opposed portions of the interior surface of thetire are movable relative to each other without generating an undueamount of heat by means of the lubricating material, which, when theassembly is used with the tire in a deflated condition, will facilitaterelative movement of contacting interior surface of the tire.